This invention relates to an improvement in a catalytic reaction process of heavy oils.
The catalytic reaction is performed by contacting crude oils with particulate solid medium, to convert the former to more useful oils. In the petroleum industry, the catalytic reaction is utilized for many processes such as cracking, desulfurization and reforming.
Usually, crude oils contain 5 to 500 ppm of nickel, 5 to 1500 ppm of vanadium, 1 to 100 ppm of iron, and 0.1 to 10 ppm of copper. Since the starting oil, on contact with transporting, storing and processing apparatuses, tends to dissolve the iron of the apparatuses, the actual content of iron in the starting oil greatly exceeds the above-mentioned value. Furthermore, since these metals tend to remain in the distillation bottom, the residual oil contains these metals in amounts at least 2 to 4 times as large as those of the starting oil. In some cases, the residual oils may contain as high as 1000 to 2000 ppm of vanadium. These metals usually exist as organic metal compounds including porphyrin-like compounds.
Thus heavy oils having high metal contents, when they are used as the starting materials for catalytic reactions, the metal components adhere to, and deposit on, the particulate solid medium employed for the reaction. If said medium has a catalytic action, the adhesion and deposition of metals thereon invite such undesirable results as reductions in the catalytic activity and the catalyst's selectivity. It becomes necessary, therefore, that the particles of the medium heavily deposited with the metals should be selectively removed.
On the other hand, if the metals can be positively adhered onto the medium by a certain catalytic method, the metal components can be eliminated from the heavy oils upon removing such a medium. Furthermore, if the particles carrying heavy deposit are separated from those carrying little deposit in the above occasion, and the latter are reused, the medium can be utilized with better effectiveness.
There is also another merit in such a separation that, since most of the metals contained in heavy oils are themselves useful, the selection of the medium particles carrying larger amounts of the metallic deposit would increase the recovering efficiency of the metal components.